Scum removal apparatus

ABSTRACT

A scum removal apparatus of a trough type including a weir movable in response to a movable element moving within a treatment pool. This apparatus includes an actuating mechanism operable in response to the movable element moving within the treatment pool and a transmission means for driving the weir, in which the transmission means includes a hydraulic pump and a control valve such that, while the actuating mechanism drives the pump, a hydraulic drive machine is driven selectively in one of two directions opposite to each other with the control valve being switched, thereby to selectively float and sink the weir above and below a water surface. 
     In a different mode of carrying out the invention, the actuating mechanism includes a plurality of cam means each having a series of projections and recesses alternating with each other, said cam means being rotatable about a rotary shaft, and the transmission means is in the form of a mechanical transmission mechanism including the rotary shaft. 
     The apparatus can be installed requiring a minimized space for installation at one side of the treatment pool and is simple in structure and easy to install.

FIELD OF TECHNOLOGY

The present invention generally relates to a scum removal apparatus forefficiently removing scum floating in a treatment pool and, moreparticularly, to the scum removal apparatus for collecting and removingthe scum with the use of a power delivered by moving elements existingin the treatment pool and without using dedicated power.

BACKGROUND ART

Since a large amount of scum gathers on a water surface in a starting orfinal settling pool, it is necessary to remove the scum efficiently. Inorder to remove the scum, the applicant has suggested the following scumremoval apparatus.

FIGS. 26 and 27 illustrate the scum removal apparatus S the applicanthas previously suggested. In a rectangular settling pool provided withthis scum removal apparatus, there is provided a plurality of (forexample, four) sprocket shafts 200 having their longitudinal axesoriented across the width of the pool, a pair of sprocket wheels 201mounted on each of the sprocket shafts 200, and left-hand and right-handendless chains trained around the respective sprocket wheels 201 of eachpair.

The scum removal apparatus is so designed as to be driven by theutilization of some or all of flights 203 secured to the endless chains202 for drawing and removing the scum (floating matter).

The scum removal apparatus is provided with a trough 205, a guidesupport sheet 206, a weir 208 and a transmission mechanism 209. Thetrough 205 is of a generally U-shaped cross-section, top side and afront side of which are opened, and is fixed in position within the poolwith its longitudinal direction oriented across the width of the pool.

The guide support sheet 206 is in the form of a generally elongated bandof a length corresponding to the length of the trough 205 and is made ofrubber material. This guide support sheet 206 is secured to the frontside of the trough 205 so as to protrude outwardly therefrom and iscapable of bending up and down by the effect of its elastic deformation.The weir 208 is of a generally triangular-sectioned hollow body whichmay often have a foaming material filled therein. This weir 208 issecured to a front side of the elastically deformable guide supportsheet 206 so as to protrude outwardly therefrom and is capable of movingup and down on respective sides of a water surface 207 while beingsupported by the sheet 206.

The up and down movement of the weir 208 is effected by an actuatingmechanism 209.

The actuating mechanism 209 comprises a rotary shaft 210 and a drive arm211. The rotary shaft 210 extends over the width of the pool while thedrive arm 211 is a single arm extending from one end of the rotary shaft210 in a direction perpendicular thereto. A free end of the drive arm211 is provided with a cam plate 213 having a cam surface defined atbottom thereof. The cam surface has two cam projections 213a and 213cand a recess 213b delimited between the cam projections 213a and 213c,all defined on the cam surface. Rollers 214 protruding from one end ofthe flights 203 (movable members) are used to move the cam plate 213 todrive the drive arm 211 and an operating arm 212 so that the weir 208can be driven up and down through a rod 224 and an operativelyassociated arm 225. Each of the rollers 214 is secured to a bracketconnected to one end of each flight 203 adjacent the earn plate 213.

The operating arm 212 cooperates with the rod 224 and the operativelyassociated arm 225 to form the transmission mechanism and extends in adirection towards the trough 205, which is counter to the direction ofextension of the drive arm 211. This operating arm 212 is employed oneach of the left-hand and right-hand sides of the pool.

The above described scum removal apparatus operates in the followingmanner.

When a motor not shown but installed outside adjacent to the pool ispowered, the chains 202 are driven in a direction indicated by an arrow,accompanied by a low-speed circulatory movement of the flights 203 whichare disposed on an outer circumference of the chains 202 in acircumferentially equally spaced relationship with each other. Theseflights 203 serve to drag sediments setting at the bottom of the pooland guide them towards a pit, and the sediments so guided to the pit aredischarged out of the pool by a pump not shown. As some of the flight203 travel upwardly and adjacent the water surface, the associatedrollers 214 mounted each end of those flights 203 are successivelybrought into engagement with the cam plate 213 to shift the latterupwardly.

The rollers 214 are successively brought into contact with theprojection 213a, then the recess 213b and finally the projection 213c,causing the cam plate 213 to move up and down. Specifically, when eachroller 214 is brought into engagement with the first-stage projection213a, both of the cam plate 213 and the drive arm 211 are lifted aconsiderable distance while the operating arm 212 is correspondinglylowered, causing the welt 208 to be lowered below the water surfacethrough the rod 224 and the operatively associated arm 225. At thistime, scum floating on the water surface, whichever small or large insize, are guided by the action of a flooding motion of water into thetrough 205 and is then discharged out of the trough 205.

When the roller 214 is then brought into engagement in the recess 213b,both of the cam plate 213 and the drive arm 211 are temporarily loweredwhile the operating arm 212 is lifted, causing the weir 208 to beshifted upwardly a slight distance with its upper edge broughtimmediately to a level below the water surface and, accordingly, theamount of water being flooded over the weir 208 is correspondinglyreduced. Although the amount of water is reduced, the velocity of flowof water increases conversely and, accordingly, a force necessary todraw the scum acts to a point on the water surface further away from theweir 208 and the scum even at the point further away from the weir 208is therefore drawn smoothly towards the trough 205.

However, when the roller 214 is finally brought into engagement with thesecond-stage projection 213c, the drive arm 211 carrying the cam plate213 is gain lifted while the operating arm 212 is lowered, andtherefore, the weir 208 is lowered with the consequence that a largeamount of scum having been drawn close to the weir 208 is guided intothe trough 205. In this way, since the cam plate 213 is of a generallyladder-like configuration, the draw of the scum towards the weir 208 andthe subsequent overthrow of the scum into the trough 205 are performedeffectively.

The scum removal apparatus S is installed one at each pool and, whilethe trough 205 in one scum removal apparatus S is installed so as toincline in one direction, the troughs 205 of all scum removalapparatuses S are fluid-connected with each other by means of connectingtroughs. The scum and water having flown into one of the troughs 205which is positioned at the highest level with respect to the directionof downward inclination flow by gravity to the final trough 205 at thelowest level through the intermediate trough or troughs 205 via theassociated connecting trough or troughs. The scum and the water havingflown into the illustrated intermediate trough 205 then flows into thenext succeeding trough 205 through the corresponding connecting troughat the lower level with respect to the direction of downward inclinationand are then discharged out of the treatment pool at the lowest level.It is to be noted that each connecting trough is fixed in position withits opposite ends communicated with respective holes formed in portionsof walls of the neighboring pools.

Since the scum removal apparatus S is of a type wherein the up and downmovement of the cam plate 213 is induced so that the up and downmovement of the cam plate 213 can result in an up and down movement ofthe weir 208, the rotary shaft 210 is required to extend generallyacross the width of the pool and, since the weir 208 is supportedelastically by the guide support sheet 206 made of rubber material, thenumber of the operating arms 212 extending between the rotary shaft 210and the weir 208 is not one, but two. With this structure, the drive arm211, the rotary shaft 210 and the operating arms 212 spread in a planeand, therefore, not only does it bring about an increased cost ofmanufacture, but also a large-scale construction work is required tomake them extend from one end to the other of the pool, resulting in theconstruction at the site taking a large amount of man power and that oftime.

Also, since the cam plate 213 is used to produce the up and downmovement necessary to drive the drive arm 211 upwardly a considerabledistance, there is a possibility that, if there is a ceiling above thepool, the cam plate 213 may contact the ceiling and, therefore, amanufacturer may find a difficulty in accommodating the request made bythe user.

Accordingly, the present invention has been developed to provide a scumremoval apparatus which is substantially free from the problems inherentin the conventional scum removal apparatus, which can be manufacturedcompact and at a reduced cost, and which can be easily installed.

DISCLOSURE OF THE INVENTION

The scum removal apparatus according to the present invention comprisesa trough opening upwardly and frontwardly, said trough being fixedlysupported adjacent a water surface in a treatment pool with thefrontwardly oriented opening of said trough positioned below the watersurface, said pool being provided with at least one movable element, anda weir capable of selectively floating above and sinking below the watersurface for drawing close towards the trough and damming scum afloat onthe water surface, respectively, and is characterized in that saidtreatment pool includes an actuating mechanism adapted to be repeatedlydriven in response to a movement of the movable element within thetreatment pool, and a transmission mechanism for driving the weir inresponse to the drive of the actuating mechanism, said transmissionmechanism including a hydraulic pump adapted to be driven by saidactuating mechanism, a hydraulic drive machine for driving the weir, anda control valve for selectively switching the hydraulic drive machine inone of first and second directions as a result of being switched by theactuating mechanism, and in that said actuating mechanism drives thehydraulic pump and also switches the control valve so that the hydraulicdrive machine can be driven in one of two directions opposite to eachother to cause the weir to selectively float above and sink below thewater surface.

The present invention is also characterized in that, in the abovedescribed scum removal apparatus, said actuating mechanism is amechanism including a plurality of cam means each having a series ofprojections and recesses alternating with each other and a memberassociated with the cam means, said cam means being arranged along apath through which said movable element moves, and said member beingrotated around a rotary shaft which is rotatable about an axis alignedwith the direction of movement of the movable element in response to themovement of the movable element.

In the above described scum removal apparatus, said transmission meansis characterized in that it comprises a mechanical transmissionmechanism including the rotary shaft. In this scum removal apparatus,said transmission mechanism is characterized in that it comprises adevice utilizing a hydraulic pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the entire apparatus according to oneembodiment of the present invention;

FIG. 2 is a front elevational view showing one end portion of a trough;

FIG. 3 is a plan view of a flight;

FIG. 4 is a system diagram showing a hydraulic circuit;

FIG. 5 is a front elevational view of a position adjusting mechanism fora lever;

FIG. 6 is a sectional view of the position adjusting mechanism for thelever;

FIG. 7 is a sectional view showing a position adjusting mechanism for alink chain;

FIG. 8 is a side view showing a bendable lever;

FIG. 9 is a perspective view showing a lever actuating mechanism of atype employing a magnet;

FIG. 10 is a side view of the lever actuating mechanism of the typeemploying the magnet;

FIG. 11 is a plan view showing another embodiment in which a shoe isdisplaced in position;

FIG. 12 is a side view showing an embodiment in which the lever isemployed in the form of a cam;

FIG. 13 is a cross sectional view taken along the line A--A in FIG. 14,showing an embodiment in which a rotary actuator is employed for ahydraulic drive machine;

FIG. 14 is a plan view of FIG. 13;

FIG. 15 is a plan view showing the entire scum removal apparatusaccording to one embodiment of the present invention;

FIG. 16 is a longitudinal sectional view of thereof;

FIG. 17 is a sectional view, taken from front, showing an operativeconnection between a roller and a cam plate;

FIG. 18 is a perspective view showing an operative connection between arotary shaft and a weir;

FIG. 19 is a side sectional view showing an embodiment in which atransmission means is constituted by a hydraulic means;

FIG. 20 is a diagram showing a hydraulic circuit thereof;

FIG. 21 is a sectional view showing an operative linkage from the camplate to the link chain;

FIG. 22 is a side view showing an embodiment in which the cam plate isof a separable type;

FIG. 23 is a side sectional view showing an embodiment in which thetransmission means is employed in the form of a link chain;

FIG. 24 is a sectional view thereof;

FIG. 25 is a side sectional view showing an embodiment applicable wherethe settling pool is of a two-story tank design;

FIG. 26 is a plan view showing an example of the conventional scamremoval apparatus; and

FIG. 27 is a perspective view showing the actuating mechanism employedin the conventional scum removal apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

To describe the present invention in more detail, reference will be madeto the accompanying drawings.

FIG. 1 to FIG. 4 illustrate one embodiment of the present invention. Inthis embodiment, reference numeral 1 represents a starting or finalsettling pool (treatment pool). This settling pool 1 when viewed fromabove represents a generally rectangular shape, and reference numeral 2represents a side wall extending in a lengthwise direction of thepool 1. Within this settling pool 1, there is provided a plurality ofrotary shaft 3 and a pair of sprocket wheels 4 mounted on opposite endsof each rotary shaft 3, left-hand and right-hand endless chains 5 beingtrained around the sprocket wheels 4 on each of the rotary shaft 3. Theendless chains 5 carry a plurality of flights 6. FIG. 3 illustrates aportion of each flight 6 as viewed from above, and the respective flight6 is provided with a chain bracket 7 to which the associated chain 5 isconnected and is also provided, at a portion adjacent one end thereof,with a shoe 8 adapted to be slidingly guided along a guide rail (notshown) at a lower circumference thereof. One end of the flight 6 isprovided especially with a roller 9 through a bracket (not shown) forthe scum removal apparatus of the present invention. Only this roller 9is provided on a left-hand side with respect to the direction of travelof the flights 6, but both of the chain bracket 7 and the shoe 8 areprovided symmetrically on left-hand and right-hand sides.

At one end the settling pool 1 with respect to the longitudinaldirection thereof, there is disposed a generally U-sectioned trough 10extending transversely of the longitudinal direction of the pool 1 andhaving its opposite ends secured to the opposite walls of the pool 1 bymeans of corresponding brackets 11. The trough 10 has its top and afront upper portion both opening, and also has its opposite ends towhich respective side plates 12 are secured so as to protrudefrontwardly away (left side of FIG. 1) from the respective trough 10.The front upper opening of the trough 10 is positioned below a watersurface 15 within the pool 1. This trough 10 is perforated at its bottomwall in communication with a conduit 15 positioned below the trough 10for the discharge of scum out of the pool 1. A support shaft 14 of alength slightly greater than the length of the trough 10 is rotatablysupported between the side plates 12. A gap between the support shaft 14and a front wall 10a of the trough 10 is closed by a seal 16.

A generally triangular-sectioned hollow float (weir) 17 has a baserigidly secured to the support shaft 14 and is rotatable. This float 17extends a length between the side plates 12, and a side seal 19 isprovided between a side face of the float 17 and the side plates 12 forsliding movement together with the side plates 12. The float 17 iscapable of selectively floating above the water surface 15 and sinkingbelow the water surface 15 to draw and dam the scum, respectively.

The support shaft 14 has its opposite ends extending outwardly from theopposite ends of the trough 10, one (or both) of said ends of thesupport shaft 14 having a bent support arm 20 rigidly mounted thereon.This arm 20 has its free end formed with a slot 20a.

Above the free end of the support arm 20 is fitted a generally U-shapedcylinder bracket 22 extending vertically and having upper and lower endsprovided with horizontally extending projections. The projection at thelower end of the bracket 22 is also formed with a slot while the upperend of the bracket 22 has a double-acting cylinder (hydraulic drivemachine) 21 mounted thereon. A rod 27 extending downwardly from thecylinder 21 is coupled through the above described slot with atransmission rod 28 rotatably supported by a bracket 23 secured to anouter surface of one of the side plates 12 of the trough 10. It is to benoted that a manually operable lever 24 is provided on an upper end ofthe cylinder bracket 22 and that on the float 17 is mounted an auxiliaryfloat 25 which moves up and down with respect to the water surface 15.In place of the auxiliary float 25, an auxiliary float 26 of a typewhich ride on the float 17 when the latter is lowered may be placedafloat the water surface 15.

Reference numeral 30 represents a hydraulic pump installed alongside thepool 1 and is mounted above a tank 31 serving as a support bench. Thishydraulic pump 30 is of any commercially available model and is of amanually operated type having a manually operable lever 30a and, byreciprocatingly moving the manually operable lever 30a, oil can bepumped from the tank 31. As shown in FIG. 4, reference numeral 32represents a check valve operable to allow an accumulator 33 toaccumulate oil under pressure. Reference numeral 34 represents apressure gauge, reference numeral 35 represents a relief valve, andreference numeral 36 represents a shut-off valve. Reference numeral 37represents a hydraulic pressure control valve which is of a two-positionclosed cross type and is provided with a return spring 38 and aswitching lever 39.

A bearing 40 is mounted atop the tank 31, and two bearings 42 and 43 arealso rigidly mounted on a support frame 41. A first shaft 44 foractuating the manually operable lever 30a is mounted on these bearings40, 42 and 43 for reciprocal movement in a direction lengthwise thereof.Between the bearings 42 and 43, there is provided a first return spring45 and a spring seat 46. A plurality of first actuating mechanisms 50extending a lengthwise direction thereof are mounted on a support frame47. This mechanism 50 is comprised of a plurality of first lever 51 anda corresponding number of link chains 52. The first levers 51 aresequentially pivoted in contact with some of the shoes 8 as they rotate,pulling the associated link chain 52 to move the first shaft 43 so thatthe hydraulic pump 30 can be driven in a direction required to pump theoil from the tank 31. Return of the first shaft 43 in the oppositedirection is effected by the action of the return spring 44. Since thereciprocal motion of the first shaft 43 is successively effected as theshoes 8 rigid with the flight 6 are sequentially brought into contactwith the levers 51, the hydraulic pump 30 can be repeatedly driven togenerate the hydraulic pressure. The hydraulic pressure so generated issubsequently accumulated in the accumulator 33.

Reference numeral 60 represents a second actuating mechanism including aplurality of second lever 61 and a corresponding number of link chain62, and a second shaft 66 extends through two bearings 64 and 65 rigidlymounted on a support frame 63. A second return spring 67 and a springseat 68 are provided between the bearings 64 and 65 and around thesecond shaft 66. This second shaft 66 is operatively associated with theswitching lever 39 of the hydraulic pressure control valve 37 to actuatethe latter. The second levers 61 are sequentially pivoted in contactwith the rollers 9 mounted on the flight 6.

Reference numerals 70 and 71 represent left-hand and right-hand throttlevalves, and reference numerals 72 and 73 represent left-hand andright-hand variable check valve, each circuit being communicated with anassociated outlet of the control valve 37.

The shoe 8 on each of the flights 8 when brought to a positionimmediately below the first levers 51 pivots the first levers 51successively as shown by the phantom lines. As the first levers 51 aresequentially pivoted, the associated link chains 52 are pulled to movethe first shaft 44 leftwards as viewed in the drawing to actuate thelever 50a so that the hydraulic pump 30 can generate an oil pressurewhich is subsequently accumulated in the accumulator 33. When thecontrol valve 37 is held in a straight position as shown in FIG. 4 (whenno second lever 61 contact the roller 9), the hydraulic pressure ishandled by the relief valve 35. At this time, the float 17 is heldafloat the water surface 15.

When the roller 9 is brought into abutment with each second lever 61,the second shaft 66 is pulled through the associated link chain 62,causing the switching lever 39 to change its position. Consequently, thecontrol valve 37 is switched onto a cross position to allow thehydraulic pressure to be supplied to the upper end of the cylinder 21through the right-hand check valve 73. Therefore, the cylinder 21 isoperated to cause the rod 27 to be extended together with thetransmission rod 28 and, by a reaction thereof, the cylinder bracket 22provided with the cylinder 21 is rocked forwards with the bracket 23serving as a receiving member. At the same time, the support arm 20 isshifted upwardly as well and the float 17 is lowered below the watersurface 15. It is to be noted that the lowering of the float 17 takesplace slowly as the left-hand throttle valve 70 acts.

When the roller 9 subsequently moves past the second lever 61, thecontrol valve 37 is returned to a straight position by the action ofsprings 67 and 38. As a result of this, the hydraulic pressure issupplied from the lower end of the cylinder 21 through the left-handcheck valve 72, causing the rod 27 to be retracted together with thetransmission rod 28 and, hence, the support arm 20 returned having beenrotated clockwise with the bracket 23 serving as a fixed receivingmember thereby to cause the float 17 to float on the water surface 15.This floating of the float 17 takes place slowly because the right-handthrottle valve 71 acts. During this time, the shoe 8 on each flight 6actuates the first levers 51 one after another and, therefore, thehydraulic pressure is progressively generated from the hydraulic pump30. It is to be noted that, when the float 17 lowers, the lowering ofthe float 17 is limited to a constant value as the auxiliary float 25(FIG. 1) acts and by the action of the relief valve 35 and, therefore,no excessive lowering of the float 17 occur.

It is to be noted that, since as shown in FIG. 2 a gap is formed betweenthe wall of the pool 1 and each end of the trough 10, a sealing plate 74is provided at front so as to close the gap. Also, reference numeral 75used in FIG. 4 represents a look bolt mounted on the bracket 22 so avoidany possible descend of the float 17 when the treatment pool 1 is emptyof water or is filled with a small quantity of water and operable toregulate an undesirable extension of the rod 27.

Some modifications will now be illustrated. FIG. 5 and FIG. 6 illustratean example in which the first and second levers 51 and 61 are mademovable horizontally. The shafts 44 and 66 are provided with sliders 80which can be fixed in position by respective bolts 81. Accordingly, thedistance of spacing between each neighboring levers can be changed asdesired.

FIG. 7 illustrates an example in which the link chains 52 and 82 arefitted movably to the associated shafts 44 and 88 by means of sliders 82and are fixed in position by means of bolts 83. Accordingly, thedistance of spacing between each neighboring levers can be changed asdesired.

FIG. 8 illustrates an example in which leading levers 85a (88a) areprovided on the first lever 85 (or the second lever 88) so that theleading levers 85a (88a) can be pivoted about corresponding hinges 87 inone direction so as to make an escapement. With this arrangement, anypossible bent or breakage of the lever 85 (88) which would occur whenthe roller 9 on each flight 6 travels in a reverse direction can beavoided.

FIG. 9 illustrate an example in which the shoe 89 or the lever 90 foreach flight 88 is made of a magnet material so that the shoe 89 and thelever 90 are detachably coupled with each other by the utilization of amagnetism developed by the magnet.

FIG. 10 illustrates a similar example in which a round shaft 94 on theside of the shoe 92 or the lever 93 is constituted by a magnet.

FIG. 11 illustrates an example in which the shoes 98 on the respectiveflights 95 are laterally offset relative to each other and, incorrespondence therewith, the levers 97 are arranged in an offsetrelationship with each other. According to this arrangement, a removalof, for example, an intermediate shoe 98 from the associated flight 95can result in a change in operative relationship of the hydraulic pumpor the control valve. Conversely, it is possible to increase theoperative relationship.

FIG. 12 illustrates a system in which a lever 101 for a control valve100 need not be employed in a plural number. A single lever 101 has alower end connected with two cams 102 through a round plate or a tube.By allowing each roller 103 to kick the cams 102 several times, thelever 101 need not be employed in a plural number. Nevertheless, thespace in which the cams 102 are provided may be made adjustable.

FIG. 13 and FIG. 14 illustrate the use of a different type for thehydraulic drive machine. In other words, the drive machine 110 is arotary actuator. A trough 111 is in the form of a semi-cylindricaltrough having its opposite ends provided with a respective side plate112 and, between these side plates 112, support shafts 113 andcorresponding seals 114 are provided at front (left) and rear (right).The support shafts 113 is provided with corresponding floats 115 eachprovided with a pair of left-hand and right-hand arms 116 protrudingoutwardly therefrom.

On the other hand, a rotary shaft 117 has its opposite ends journalledto the side plates 112, one of said opposite ends of the rotary shaft117 being drivingly coupled with a drive machine 110. The rotary shaft117 has two portions longitudinally spaced each other on whichrespective stays 118 are mounted so as to protrude upwardly. Each ofthese stays 118 has an operating arm 119 rigidly secured thereto so asto represent a generally T-shaped configuration. Each of the oppositeends of each operating arm 119 is formed into a slot 119a in which anassociated rod 120 is received while extending therethrough. Each rod120 has a lower end coupled with the associated arm 116 and has itsouter periphery on which nuts 121 and 122 are mounted in axially spacedrelationship with each other. The hydraulic drive machine 110 isreciprocatingly driven in one of opposite directions by means of acircuit including a tank 123 and a hydraulic pressure control valve 124.Accordingly, when the drive machine 110 is rotated in one of theopposite direction, the operating arms 119 are rotated in the samedirection by means of the rotary shaft 117 until the operating arms 119are brought: into abutment with the nuts 122 and, thereafter, the rods120 are lowered, causing one of the floats 115 to be lowered below thewater surface. On the other hand, when the drive machine 110 is drivenin the other of the opposite directions, the other of the floats 115 islowered below the water surface while said one of the floats 115 islifted above the water surface.

FIG. 15 to FIG. 18 illustrate another embodiment of the presentinvention. In this embodiment, reference numeral 101 represents astarting or final settling pool (treatment pool). This settling pool 101when viewed from above represents a generally rectangular shape, andreference numeral 102 represents a side wall extending in a lengthwisedirection of the pool 1. Within this settling pool 101, there areprovided a plurality of rotary shaft 103 and a pair of sprocket wheels104 mounted on each rotary shaft 103, left-hand and right-hand endlesschains 105 being trained around the sprocket wheels 104 on each of therotary shaft 103. The endless chains 105 carry a plurality of flights106 spaced an equal distance from each other over the circumference ofthe endless chains 105. Each of the flights 106 may be made of anymaterial such as wood, plastics or any other suitable material.

FIG. 17 illustrates a fragmentary portion of one of the flights 106 and,as shown therein, a left-hand end of each flight 106 with respect to thedirection of movement thereof is provided specially with a roller 109for the scum removal apparatus through a corresponding bracket which isnot shown.

At one end the settling pool 101 with respect to the longitudinaldirection thereof, there is disposed a generally U-sectioned trough 110extending transversely of the longitudinal direction of the pool 101.This trough 110 has at its opposite ends flanges 110a and 111afluid-connected with respective connecting troughs 111 (FIG. 15) fixedin position by means of brackets while the connecting troughs 111 extendthrough side walls 102 of the settlement pool 101.

The trough 110 has its top and a front upper portion both opening, andalso has its opposite ends to which respective side plates 112 aresecured so as to protrude frontwardly away from the flanges 110a. Thefront upper opening of the trough 110 is positioned below a watersurface 115 within the pool 101. A support shaft 114 of a lengthslightly greater than the length of the trough 110 is rotatablysupported between the side plates 112. A gap between the support shaft114 and a front wall 110b of the trough 110 is closed by a seal 116.

A generally triangular-sectioned hollow float (weir) 117 has a baserigidly secured to the support shaft 114 and is rotatable. This weir 117has a length sufficient to extend between the side plates 112, and aside seal 119 fitted to each end face thereof slides along a side faceof the trough 110. The weir 117 is capable of selectively floating abovethe water surface 115 and sinking below the water surface 115 to drawand dam the scum, respectively. It is to be noted that the support shaft114 is securely supported by bearings fixed to the trough 110, whichbearings are not shown.

On the other hand, a mechanism for selectively floating and sinking theweir 117 is so constructed as will now be described.

In the first place, an actuating mechanism 120 includes two brackets121, a cam plate 122 and a rotary shaft 123. The brackets 121 aresecured to one of the opposite side walls 102 and spaced in a directionlengthwise of the settling pool 101, and the rotary shaft 123 issupported by the brackets 121 so as to extend parallel to the side wall102. This rotary shaft 123 has two support arms 124 extending laterallytherefrom and carries a cam plate 122 mounted on the support arms 124.

The cam plate 122 is in the form of a generally elongated plate havingits undersurface formed with a series of projections 122a and recesses122b alternating with each other. Each of the recesses 122b has adeepest portion depressed inwardly to a level lower than the level of anupper end of each roller 109 whereas a lowermost end of each of theprojections 122a terminates at a level further lower than the lower endof the respective roller 109.

The rotary shaft 123 is in the form of a single elongated shaftextending towards the trough 110 with one end thereof rotatablyextending through and supported by a bracket 125 secured to a rearportion of the trough 110. One end of the rotary shaft 123 is providedwith a drive lever 127 rigidly connected thereto so as to extendlaterally outwardly therefrom for moving up and down a driven lever 126secured to the support shaft 114. The drive lever 127 has a free endcarrying a roller 128. It is to be noted that a lower end portion of thecam plate 122 where the projections and the recesses are formed istapered and, at the same time a free end of the cam plate 122 is alsoshaped so as to taper outwardly. A transmission means is constituted bythe rotary shaft 123, the drive 1ever 127 and the driven 1ever 126.

When each roller 109 is successively brought into contact with theprojections 122a of the cam plate 122 as the flights 106 undergo acirculatory motion with the rollers 109 successively brought intoregister with the cam plate 122, the roller 109 shifts upwardly aboutthe rotary shaft 123. Accordingly, the drive lever 127 is shiftedupwardly through the rotary shaft 123, accompanied by a correspondingupward shift of the driven lever 126 and, consequently, the weir 117 islowered considerably below the water surface allowing scum to be drawninto the trough 110 together with water.

When the roller 109 is subsequently brought into the recess 122b, thecam plate 122 is lowered about the rotary shaft 123, causing the rotaryshaft 123 to be returned a little and, therefore, the weir 117 is mowedwith its upper end positioned several centimeters below the watersurface. At this time, since the water surface flows at a rapid speed,scum located further away from the trough 110 can be drawn close towardsthe trough 110 as described hereinbefore and is finally drained into thetrough 110. By repeating this cycle, the weir 117 cyclically moves upand down below the water surface, and as the roller 109 moves past thecam plate 122, the rotary shaft 123 returns allowing the weir 117 to beafloat above the water surface 115, thereby interrupting the flow of thescum into the trough 110.

FIG. 19, FIG. 20 and FIG. 21 illustrate a different embodiment in whicha hydraulic pressure (oil pressure) which is a fluid pressure isutilized as a transmission means. In this embodiment, a mechanism forselectively floating and sinking the weir 117 is so constructed as willnow be described.

In the first place, an actuating mechanism 130 includes three brackets131, a cam plate 132 and a rotary shaft 133. The rotary shaft 133 is ofa short length and carries the cam plate 132 secured thereto through twospaced apart support arms 134 protruding laterally from the rotary shaft133. When the cam plate 132 is rotated by each roller 109 about therotary shaft 133, a hydraulic pump 136 is repeatedly driven through alink mechanism 135 to allow an accumulator 137 to accumulate pressure.

An other portion of the rotary shaft 135 is fitted with a switching camplate 158 which undergoes a rotatory motion independently of the camplate 132. When each roller 109 is brought into contact with this camplate 138, the cam plate 138 is rotated around the rotary shaft 133independently of the cam plate 132 to switching a hydraulic pressurecontrol valve 140 of two-position closed cross type through a linkmechanism 159.

Reference numeral 141 represents a driven lever adapted to bereciprocatingly pivoted by a cylinder 142.

Reference numeral 143 in a hydraulic circuit represents a check valveoperable to allow the accumulator 157 to accumulate pressure oil.Reference numeral 144 represents a pressure gauge, reference numeral 145represents a relief valve, and reference numeral 146 represents ashut-off valve. The control valve 140 is provided with a return spring147 and a switching 1ever 148.

Reference numerals 150 and 151 represent left-hand and right-handthrottle valves, and reference numerals 152 and 153 represent left-handand right-hand variable check valve, each valve being communicated withan associated outlet or inlet of the control valve 140.

When each roller 109 is brought into contact with the cam plate 132, therotary shaft 133 is repeatedly rotated in the manner describedhereinabove and, accordingly, the pump 136 is driven to allow theaccumulator 137 to progressively accumulate pressure. When the controlvalve 140 is in a straight position, the hydraulic pressure iscontrolled by the relief valve 145. The weir 117 is held afloat on thewater surface.

When the respective roller 109 is brought into abutment with the camplate 138, the control valve 140 is switched onto a cross positionthrough the link mechanism 139, allowing the hydraulic pressure to besupplied to a lower end of the cylinder 142 through the right-hand checkvalve 153. Accordingly, the weir 117 is lowered below the water surface.It is to be noted that the lowering of the weir 117 takes place slowlyas the left-hand throttle valve 150 acts.

When the roller 109 subsequently moves past the cam plate 138, thecontrol valve 140 is returned to the straight position. As a result ofthis, the hydraulic pressure is supplied to an upper end of the cylinder142 through the left-hand check valve 152, causing the weir 117 to floatupwardly. This floating of the float 117 takes place slowly because theright-hand throttle valve 151 acts. During this time, the accumulator137 progressively accumulate the hydraulic pressure.

Hereinafter, another modification will be illustrated. As shown in FIG.22, arrangement may be made that there is provided a plurality of tubes162 that can be fixed to the rotary shaft 160 by means of bolts 161while slidably mounted thereon. The support arms 163 are fitted to thesetubes 162 with cam plates 164 mounted thereon. The cam plates 164 can beadjustable in position along the rotary shaft 160 and, at the same time,a desired number of the cam plates 164 can be employed. Therefore, thetiming of operation can be designed as desired according to demands madeby the user.

FIG. 23 and FIG. 24 illustrate an example in which the transmissionmeans is constituted by link chain 170. A rotary shaft 172 carrying acam plate 171 is provided with a lever 173 to which one end of the linkchain 170 is anchored. Pulleys 174 are disposed above the pool and thechain 170 is trained around these pulleys 174 with its other endconnected to a driven lever 175. Accordingly, when each roller 176 isbrought into abutment with the cam plate 171, the chain 170 is pulleddownwardly with the driven lever 175 consequently shifted upwardly tolower the weir 177. The depth to which the weir 177 is lowered dependson cam irregularities of the cam plate 171. It is to be noted that thelever 173 may be counteracted with a return stopper.

FIG. 25 illustrates an embodiment in which the present invention isapplied to a deeper pool of a two-story settling pool. Referencenumerals used in this embodiment are the same as those employed in theembodiment shown in FIG. 23. Even in this embodiment, the scum removalapparatus can be manufactured compact and can easily be installed atsite.

It is to be noted that the cam plate may have its surface orientedhorizontally or inclined upwardly while the rollers are so arranged asto retain an operatively associated relationship therewith. Conversely,the cam plate may be provided on the flights while the rollers may beprovided on the rotary shaft.

INDUSTRIAL APPLICABILITY

As hereinbefore fully described, the scum removal apparatus according tothe present invention is installed at a treatment pool such as thestarting or final settling pool, is useful as a convenient apparatus forremoving scum afloat on a water surface, is applicable to allapparatuses designed to remove scum by the maximized utilization of thepower delivered by movable members existing in the treatment pool, andcan particularly be manufactured compact in size, at a reduced cost andto meet a requirement that it can be installed at site.

What is claimed is:
 1. A scum removal apparatus for a treatment poolcomprising;a trough opening upwardly and frontwardly, said troughincluding means for fixedly supporting the trough adjacent a watersurface in the treatment pool with the frontwardly oriented opening ofsaid trough positioned below a water surface of the treatment pool, atleast one movable element for location in the treatment pool; a weirlocated adjacent the trough including means for selectively floatingabove and sinking below the water surface for drawing close towards thetrough and damming scum floating on the water surface, respectively, anactuating mechanism including means for being repeatedly driven inresponse to movement and contact with the movable element within thetreatment pool, a transmission mechanism operatively connected to theactuating mechanism for driving the weir in response to the drive of theactuating mechanism, said transmission means including a hydraulic pumpincluding means for being driven by said actuating mechanism, ahydraulic drive machine for driving the weir, and a control valve forselectively switching the hydraulic drive machine in one of first andsecond directions as a result of being switched by the actuatingmechanism, so that said actuating mechanism drives the hydraulic pumpand also switches the control valve so that the hydraulic drive machinecan be driven in one of two directions opposite to each other to causethe weir to selectively float above and sink below the water surface. 2.The scum removal apparatus as claimed in claim 1, wherein there are twophysically distinct actuating mechanisms each mechanism including ashaft operatively connected to a plurality of levers by a link chainoperatively connected to each lever.
 3. The scum removal apparatusaccording to claims 2, wherein there are support frames for pivotallymoving the levers.
 4. The scum removal apparatus according to claim 1,wherein the movable element includes a shoe, chain bracket and a rollerat one end.
 5. A scum removal apparatus for a treatment poolcomprising:a trough opening upwardly and frontwardly, said throughincluding means for fixedly supporting the trough adjacent a watersurface in the treatment pool with the frontwardly oriented opening ofsaid trough positioned below the water surface, at least one movableelement for location in the treatment pool, a weir located adjacent thetrough including means for selectively floating above and sinking belowthe water surface for drawing close towards the trough and damming scumfloating on the water surface, respectively, an actuating mechanismincluding means for being repeatedly driven in response to movement andcontact with the movable element within the treatment pool, atransmission mechanism operatively connected to the actuating mechanismfor driving the weir in response to the drive of the actuatingmechanism, said actuating mechanism including a plurality of cam meanseach having a series of projections and recesses alternating with eachother and a member operatively connected with the cam means, said cammeans being arranged along a path through which said movable elementmoves, a rotary shaft which is rotatable about an axis aligned with thedirection of movement of the movable element and is rotatable bymovement of the movable element, and said member being rotatable aroundthe rotary shaft.
 6. A scum removal apparatus as claimed in claim 5,wherein said transmission means is a mechanical transmission mechanismincluding the rotary shaft.
 7. A scum removal apparatus as claimed inclaim 5, wherein said transmission mechanism is a device operable byhydraulic pressure.